<template>
    <div>

    </div>
</template>
<script>
let a = 1;
typeof a === 'number' ? console.log(a + 'a是数字') : console.log('a不是数字');
console.log(typeof a);
let b = new Number(1);
typeof b === 'number' ? console.log('b是数字') : console.log(b + 'b不是数字');
console.log(a instanceof Number); // false
console.log(b instanceof Number); // true
console.log(a);
console.log(b);
let c = ['1', '2', '3', 'dsdf'];
for (k of c) {
    console.log(k); // 0 1 2 3
}

</script>